Tuning in the presence of matching
From Wiki Les Houches 09
(Difference between revisions)
Current revision (13:43, 13 June 2009) (view source) (→Chart the problem. Determine some Classic Examples) |
|||
| (3 intermediate revisions not shown.) | |||
| Line 1: | Line 1: | ||
| - | '''Interested parties''': | + | '''Interested parties''': ''Piergiulio Lenzi, Vitaliano Ciulli, Peter Skands, Leif Lonnblad, Simon Platzer, Jon Butterworth, Jeppe Anderson, Mario Campanelli, Markus Warsinsky, Matthew Schwartz, Peter Loch, Dieter Zeppenfeld, Giacinto Piacquadio, Paulo Francovilla +...'' |
== Chart the problem. Determine some Classic Examples == | == Chart the problem. Determine some Classic Examples == | ||
| Line 6: | Line 6: | ||
* Affect n=1 ME corrections, Pythia, Herwig, Alpgen+Herwig and Sherpa all pretty much agree. For Algen+Pythia there is a significant difference at low pT. Means that PYTHIA tune would be different for usage with & without Alpgen. | * Affect n=1 ME corrections, Pythia, Herwig, Alpgen+Herwig and Sherpa all pretty much agree. For Algen+Pythia there is a significant difference at low pT. Means that PYTHIA tune would be different for usage with & without Alpgen. | ||
| + | Piergiulio Lenzi [http://hep.fi.infn.it/CMS/Florence_integration/giulio/LesHouches/lenzi_13062009.pdf slides] | ||
| - | + | == How would low x logs/high energy limit affect tunes? == | |
| - | == | + | |
| - | + | ||
| - | How would low x logs affect tunes? | + | |
Expect extra events at with high rapidity jets due to: | Expect extra events at with high rapidity jets due to: | ||
| Line 18: | Line 16: | ||
| - | Not | + | Not addressed: |
* How dependent on matching strategy? | * How dependent on matching strategy? | ||
* Are there ways of revamping pre-matched tunes? | * Are there ways of revamping pre-matched tunes? | ||
Current revision
Interested parties: Piergiulio Lenzi, Vitaliano Ciulli, Peter Skands, Leif Lonnblad, Simon Platzer, Jon Butterworth, Jeppe Anderson, Mario Campanelli, Markus Warsinsky, Matthew Schwartz, Peter Loch, Dieter Zeppenfeld, Giacinto Piacquadio, Paulo Francovilla +...
Chart the problem. Determine some Classic Examples
Effect of ME corrections on low pT end of the Z pT distribution compared for PYTHIA, HERWIG, Sherpa, Alpgen. Some points:
- Affect n=1 ME corrections, Pythia, Herwig, Alpgen+Herwig and Sherpa all pretty much agree. For Algen+Pythia there is a significant difference at low pT. Means that PYTHIA tune would be different for usage with & without Alpgen.
Piergiulio Lenzi slides
How would low x logs/high energy limit affect tunes?
Expect extra events at with high rapidity jets due to:
- large colour singlet contribution. This will have a component with rapidity gaps, and a component where these gaps have been destroyed by UE.
- large colour octet contribution enhanced by low x logs (Jeppes's calculations).
Presumably these effects will distort min bias tunes etc, since this physics is not necessarily in the MC. The first effect actually can be modelled by HERWIG+JIMMY, to some extent at least.
Not addressed:
- How dependent on matching strategy?
- Are there ways of revamping pre-matched tunes?
